Video-based handwriting input for biometric signature data collection is provided. The invention is implemented by finding all of the relative positions among all light points of light sources when all light sources mounted on a stylus are turned ON. An image is captured including effective strokes and digital data of pen pressure with a digital camera when a user writes on a writing surface with a stylus having a light source indicating x-y coordinates of strokes. The images are time-stamped. The stylus includes a micro-switch. When the stylus touches the writing surface, the micro-switch is turned on to let the light source indicating x-y coordinates of strokes turn ON and generate a light point. Effective stroke images and digital data of pen pressure are extracted by comparing the captured images with the light point on the stylus.